MemAid is like a traditional flash-card program to help you memorise
question/answer pairs, but with an important twist: it uses a neural network
to schedule the best time for an item to come up for review.
Difficult items that you tend to forget quickly will be scheduled more often,
while MemAid won't waste your time on things you remember well.
This means your learning process becomes much more efficient,
also because the neural network gradually adapts to your personal memory model.
(more about repetitions can be found here.)

Operating System?
Currently supported are Unix and Linux.

Versions
There are a few versions of MemAid (all use the same core code written initially by David Calinski).
Here is the list of currently available versions from our project home page
(http://sf.net/projects/memaid/):

"memaid" package. It contains MemAid user interfaces written initially by David Calinski.
Currently there is a console version, and a graphical front-end
(screenshot)
that uses the free, cross-platform, fast and ligth-weight Fox GUI Toolkit.
David has aimed to have a light and portable version.

"kmemaid" package by Klemens Meyer, contains a MemAid version using the KDE libraries.
It's a graphical version that has more eye candy, and currently may offer some more fancy things
(e.g. some HTML tags, support for Unicode).
You may want to see some KMemAid
screenshots.

"pyqt memaid" package by Peter Bienstman. Another graphical client, but one that supports categories and different learning modes. Screenshots are here, docs are here. This package also contains a SuperKaramba widget that blends discreetly into your
KDE wallpaper. (see KDE-look).